As Mayor Bloomberg's main squeeze, Taylor is New York's de facto first lady.

Taylor grew up in a firmly Republican old-money family in Greenwich and attended the swanky Milton Academy and Dartmouth before heading off to Columbia Business School. After working as an investment banker at Smith Barney, in 1999 she was hired as a VP at KeySpan Energy. She soon switched over to the public sector, becoming deputy secretary for finance and housing under Governor George Pataki and then, in 2003, New York's superintendent of banks, a position that entailed regulating the state's lenders, check cashers, and mortgage industries. In 2007, Taylor stepped down—she said the newly-elected governor Eliot Spitzer "ought to have his own people" do the job—and accepted a job offer at Wolfensohn & Co., the boutique investment bank founded by James Wolfensohn, former president of the World Bank. She also serves on the boards of many institutions, from Sotheby's to the YMCA of Greater New York.

Taylor and Bloomberg have been dating since 2001. They have no plans to tie the knot. [Image via Getty]